namespace NVelocity.Util
{
	using System;
	
	/*
	* $Header: /cvsroot/nvelocity/NVelocity/src/Util/SimplePool.cs,v 1.2 2002/07/30 07:26:51 corts Exp $
	* $Revision: 1.2 $
	* $Date: 2002/07/30 07:26:51 $
	*
	* ====================================================================
	*
	* The Apache Software License, Version 1.1
	*
	* Copyright (c) 1999-2001 The Apache Software Foundation.  All rights
	* reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions
	* are met:
	*
	* 1. Redistributions of source code must retain the above copyright
	*    notice, this list of conditions and the following disclaimer.
	*
	* 2. Redistributions in binary form must reproduce the above copyright
	*    notice, this list of conditions and the following disclaimer in
	*    the documentation and/or other materials provided with the
	*    distribution.
	*
	* 3. The end-user documentation included with the redistribution, if
	*    any, must include the following acknowlegement:
	*       "This product includes software developed by the
	*        Apache Software Foundation (http://www.apache.org/)."
	*    Alternately, this acknowlegement may appear in the software itself,
	*    if and wherever such third-party acknowlegements normally appear.
	*
	* 4. The names "The Jakarta Project", "Velocity", and "Apache Software
	*    Foundation" must not be used to endorse or promote products derived
	*    from this software without prior written permission. For written
	*    permission, please contact apache@apache.org.
	*
	* 5. Products derived from this software may not be called "Apache"
	*    nor may "Apache" appear in their names without prior written
	*    permission of the Apache Group.
	*
	* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
	* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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	* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	* SUCH DAMAGE.
	* ====================================================================
	*
	* This software consists of voluntary contributions made by many
	* individuals on behalf of the Apache Software Foundation.  For more
	* information on the Apache Software Foundation, please see
	* <http://www.apache.org/>.
	*
	* [Additional notices, if required by prior licensing conditions]
	*
	*/
	
	/// <summary> Simple object pool. Based on ThreadPool and few other classes
	/// *
	/// The pool will ignore overflow and return null if empty.
	/// *
	/// </summary>
	/// <author> Gal Shachor
	/// </author>
	/// <author> Costin
	/// </author>
	/// <author> <a href="mailto:geirm@optonline.net">Geir Magnusson Jr.</a>
	/// </author>
	/// <version> $Id: SimplePool.cs,v 1.2 2002/07/30 07:26:51 corts Exp $
	/// 
	/// </version>
	public sealed class SimplePool
	{
		public int Max
		{
			get
			{
				return max;
			}
			
		}
		/*
		* Where the objects are held.
		*/
		private System.Object[] pool;
		
		/// <summary>  max amount of objects to be managed
		/// set via CTOR
		/// </summary>
		private int max;
		
		/// <summary>  index of previous to next
		/// free slot
		/// </summary>
		private int current = - 1;
		
		public SimplePool(int max)
		{
			this.max = max;
			pool = new System.Object[max];
		}
		
		/// <summary> Add the object to the pool, silent nothing if the pool is full
		/// </summary>
		public void  put(System.Object o)
		{
			int idx = - 1;
			
			lock(this)
			{
				/*
				*  if we aren't full
				*/
				
				if (current < max - 1)
				{
					/*
					*  then increment the 
					*  current index.
					*/
					idx = ++current;
				}
				
				if (idx >= 0)
				{
					pool[idx] = o;
				}
			}
		}
		
		/// <summary> Get an object from the pool, null if the pool is empty.
		/// </summary>
		public System.Object get()
		{
			int idx = - 1;
			
			lock(this)
			{
				/*
				*  if we have any in the pool
				*/
				if (current >= 0)
				{
					/*
					*  take one out, so to speak -
					*  separate the two operations
					*  to make it clear that you
					*  don't want idx = --current; :)
					*/
					
					idx = current;
					current--;
					
					/*
					*  and since current was >= 0
					*  to get in here, idx must be as well
					*  so save the if() opration
					*/
					
					return pool[idx];
				}
			}
			
			return null;
		}
		
		/// <summary>Return the size of the pool
		/// </summary>
	}
}